Gas treatment units and/or CO2 capture units using amine wash processes and/or distillation units comprise columns for material and/or heat exchange between a gas and a liquid, which can be for example liquid or gaseous fluid absorption and regeneration columns. These columns operate under counter-current or co-current gas/liquid flow conditions.
The columns used in these gas treatment and/or CO2 capture and/or distillation and/or dehydration units generally operate on the principle of material and/or heat exchange between the gas and the fluid that circulate in the columns. FIG. 1 shows a particular case of a gas treatment column top (1) equipped with a distributor tray. Conventionally, this gas treatment column (1) comprises several sections (3) filled by a contactor, notably a packing, and a distributor tray (2) is arranged above each section (3). Gas/liquid contactor (3) contacts gas (G) with liquid (L) so as to allow exchanges.
For example, standard distributors (2) used in absorption/regeneration or distillation columns generally consist of a collector/distributor tray equipped with chimneys (4) or casings allowing passage of the gas (see FIG. 2). Distribution of the liquid occurs through passage thereof in orifices (5) positioned in the lower part of tray (2) and distribution of the gas occurs through casings (4). Each casing (4) allows passage of the gas, according to the counter-current or co-current operating mode, from the lower part of the column to the upper part of column (1), or from the upper part to the lower part. Casings (4) project beyond one side of tray (2) and they are perpendicular thereto. Each casing (4) consists of several walls, parallelepipedic or cylindrical for example, which delimit an inner volume that is open on either side of tray (2). In order to prevent the liquid from flowing into casings (4), the gas outlet or inlet opening above the tray (according to the counter-current or co-current mode) is preferably covered by a cap (also referred to as bevel). The purpose of the distributor tray is to distribute liquid (L) homogeneously onto gas/liquid contactor (3).
In order to optimize exchanges between gas and liquid, many distributor trays have been designed. These distributor/collector trays are mainly divided into two major families:
distributor/collector systems with chimneys, as described in patent applications GB-1,169,878A, U.S. Pat. Nos. 4,808,350A, 4,472,325A, 4,427,605A, 4,839,108A, FR-2,203,659. For this type of system with chimneys, the liquid is distributed via orifices provided on the tray or via liquid passage chimneys equipped with orifices or slots (see example of FIG. 2), and the gas is distributed through gas passage chimneys or casings. Distribution of the liquid occurs through orifices provided on the tray or by means of liquid passage chimneys. It is well known that liquid distribution through orifices provided on the tray does not allow a high liquid flow rate flexibility to be obtained. Liquid distribution using chimneys provides good flexibility but does not allow to obtain homogeneous distribution of the liquid on the contactor without a large number of orifices or chimneys, thus leading to a complex and heavy tray (large number of liquid passage chimneys),
systems with distributor casings provided with a dedicated feed distribution (upstream collecting system or intermediate feed), as described in patent applications U.S. Pat. Nos. 4,909,967, 4,816,191, 4,981,265, DE-2,752,391, WO-8,802,647, FR-2,569,129, or distributor/collector systems with casings for passage of the gas as described in patent applications U.S. Pat. Nos. 4,689,183, 5,132,055, 4,432,913. These distributor types are most often provided with liquid distribution systems arranged on the gas passage casings.
Furthermore, distributor trays fitted with deflectors for liquid distribution on the contactor have been developed (see for example patent applications US-2010-019,061, US-2009-0,134,063, U.S. Pat. No. 5,403,561, CN-100,364,652). However, most of them are designed for columns operating under co-current conditions where the purpose of the deflector is to disperse the liquid in form of droplets. Now, in liquid distributors used in counter-current processes, the formation of droplets likely to be carried along by the gas to the detriment of the process efficiency needs to be prevented. Liquid flows at the deflector outlet in counter-current processes have to be dense jets. Moreover, the purpose of these deflectors is to provide homogeneous distribution of the fluid in all directions.
The flow of liquid in packings is different depending on the packing technology. On a random packing, the dispersion (diffusion) of the liquid in the packing bed is isotropic. On the other hand, on a structured packing, the plates greatly restrict the liquid dispersion orientation to directions parallel to the plates (a certain secondary dispersion perpendicular to the plates can however occur due to the existence of small openings on the plates, generally orifices). Dispersion in directions perpendicular to the plates occurs subsequently upon moving to the next packing section whose plates are generally positioned at 90°, but it is not ensured for the first section (upper section). For a conventional distributor tray, as the distribution of the liquid is not oriented, the unexploited surface area on the first structured packing section is estimated at 70%.
To overcome these problems, the present invention relates to a distributor tray for a column intended for heat and/or material exchange between a gas and a liquid. The tray comprises gas passage means, liquid passage chimneys and distribution means for distributing the liquid with a preferred orientation. Thus, the invention allows to provide a good liquid distribution quality and to improve the gas/liquid exchange efficiency on at least a first structured packing section using oriented distribution means.